Liquid crystal displays (LCDs) have been widely applied in a variety of electronic products. Most of the LCDs are backlight type liquid crystal displays each including a liquid crystal panel and a backlight module. The backlight modules may be divided into side-light type backlight modules and direct-light type backlight modules according to different incident positions of light sources.
In order to improve brightness of the backlight modules, a prism light guide plate appears. Since scattering occurs at the prism light guide plate, thus light enters a panel with a large angle of incidence, and display effects will be affected. If the angle of incidence of a light source is too large, an emergence angle cannot completely reverse propagation directions of the light. Thus, normal backlighting cannot be formed in a front of the panel. Further, since light deflection occurs in an existing transparent display device, thus, objects behind the prism light guide plate cannot be seen through the prism light guide plate. Meanwhile, the prism light guide plate may cause scenery behind the prism light guide plate blurred.